This invention relates generally to prosthetic devices and specifically to an artificial skeletal ligament.
A ligament is a band of tough tissue which serves to connect the articular extremities of bones or to support an organ. Skeletal ligaments flexibly stabilise joints and consequently must be able to withstand considerable forces. Ligaments are often damaged by being subjected to excessive forces. Ligaments rarely mend completely and the working of the damaged joint may be permanently impaired.
Surgical repair of a torn ligament is often difficult and unsatisfactory not only because a long period of convalescence is required but also because the repaired joint may move in directions which are not normally allowed causing pain in the joint and undue wear to the skeletal members.
Various artificial ligaments have been proposed for replacement of damaged natural ligaments.
United Kingdom Pat. No. 1526762 (Richards Manufacturing Company) disclosed a prosthetic ligament comprising an elongate flexible portion with enlarged head at each end, the head serving to secure the flexible portion in bores through the skeletal member in which the ligament is attached.
U.S. Pat. No. 3,973,277 (Semple et al) disclosed a similar arrangement in which the flexible portion is secured in bores in the skeletal members by means of tapered porous plugs. German Offenlegungschrift No. 2836921 (Sigri Elektrographit GmbH) discloses use of a textile strip secured at each end to a skeletal member. A woven prosthesis may have apertures of varying sizes, as disclosed in U.S. Pat. No. 4,255,820 to control ingrowth of tissue.
European Patent Application No. 126520 (Seedhom, Ellis & Fujikawa) discloses a woven fabric prosthesis ligament having the form of a tube, one end of which has two slits on opposite sides of the tube. The end of the tube adjacent the slits is sealed by stitching to form a pocket to receive a bone plug during installation of the prosthesis. The opposite end of the tube has an elongate slit, open at the end to receive a second bone plug. The tubular structure is formed by stitching a flat ribbon of woven fabric.
Stitching of the prosthesis does not remove the selvedge which may cause irritation and may be a source of structural weakness. In addition stitching requires a separate manufacturing step after weaving the ribbon.
It is an object of this invention to provide a prosthetic ligament which does not incorporate stitching or other separate means of fastening the woven portions.
A prosthetic ligament in accordance with this invention comprises an elongate woven fabric member having two ends, including a portion woven in the form of a tube, a tail section extending between the tubular portion and a first end, the tail section having a tubular configuration with a single longitudinal opening, a pocket extending from the tubular portion towards the second end of the member and having a tubular configuration with a single longitudinal opening, and a tightly woven portion extending from the pocket towards said second end, wherein the member comprises a unitary woven structure.
Weaving of the prosthesis as a unitary structure avoids the need for any subsequent sewing. The structure is also stronger and does not have a selvedge which could cause irritation.
The prosthesis is preferably woven in a leno or mock leno weave having apertures adapted to receive ingrowth of tissue. Preferred embodiments of the invention incorporate 10 to 50 apertures per cm.sup.2, more preferably 15 to 36 apertures per cm.sup.2. A uniform distribution of apertures is preferred. The prosthesis may be composed of fibres sold under the Trade Marks `Terylene` or `Dacron` or other polyester compounds although alternative artificial or natural fibres may be employed.
A cord or thread may be attached to the second end to facilitate threading of the prosthesis through the skeletal members.
In use of the prosthesis, bone plugs are removed from the skeletal members forming apertures which partially penetrate each skeletal member. Smaller diameter bores are then made through the skeletal members from the bottoms of the apertures. The prosthesis is threaded through the apertures using the cord and a bone plug located in the pocket. The prosthesis is then pulled so that the bone plug is relocated in the aperture, securing the prosthesis in the first skeletal member. The second bone plug may then be placed in the tail portion and reinserted in the respective aperture and sutured to secure the other end of the prosthesis.